1. Field of the Invention
Example embodiments relate to semiconductor devices and methods of forming semiconductor devices. More specifically, example embodiments relate to semiconductor devices including a growth promoting layer and a growth inhibiting layer, as well as methods of forming semiconductor devices including a growth promoting layer and a growth inhibiting layer.
2. Description of the Related Art
Due to increases in semiconductor packaging densities, the dimensions of electrical contacts have been reduced, thereby increasing height-to-width or aspect ratios of the electrical contacts and openings in which the electrical contacts are formed. With increasing aspect ratios, adequate metal step coverage of surfaces within the opening has become more difficult to achieve, especially at temperatures lower than about 200° C. As the aspect ratio increases, metal deposited at colder temperatures fails to produce good step coverage due to “necking” (or “cusping”) at the top corners of the openings in which the electrical contacts are being formed. Necking gives rise to the formation of a void within the contact formed in the opening.
FIG. 1 illustrates an example of a void created due to necking. In particular, FIG. 1 illustrates an insulating layer 205 on a substrate 200 having an impurity doped region 203 formed therein that is exposed by an opening. A diffusion barrier layer 207 (such as TiN diffusion barrier layer) is formed in the opening and on the exposed surface of the impurity doped region 203. A conductive layer 209 is formed on the diffusion barrier layer 207 on the external surfaces as well as in the opening. As shown in FIG. 1, because of the high aspect ratio of the contact hole, a void 211 is formed in the opening because of the formation of the overhang portion 215 that blocks further deposition of the conductive layer 209 in the opening.
Voids, such as the void 211 illustrated in FIG. 1, formed within an opening during the formation of an electrical contact may lead to malfunctions. Accordingly, necking tends to lead to reliability and yield problems as a result of voids created during the formation of the electrical contact. In an attempt to address this and other problems, various techniques have been developed and employed including Chemical Vapor Deposition (CVD) of metals, aluminum reflow, etc.